There is a system in which “information” created from a number of vehicles is collected via a “network” to be utilized. A sudden braking notification system is an example of such a system. The sudden braking notification is a service of notifying a plurality of vehicles existing behind a vehicle that brakes hard suddenly of occurrence of sudden braking.
The sudden braking notification system frequently collects information of a speed and a position of a vehicle so as to detect sudden braking in real time and accurately grasp an anteroposterior relationship of vehicles. In addition, there is a system in which information is collected from a number of airplanes or ships so as to achieve safe traffic. If these systems constantly collect a large amount of information, a large load is applied to the network. As a technology to control the load, the following technologies are disclosed.
PTL 1 discloses a vehicle that regularly transmits data to surrounding other vehicles while changing transmission power, that is, a communication distance. Accordingly, the vehicle transmits data to a nearby vehicle frequently and to a distant vehicle less frequently.
PTL 2 discloses a vehicle that transmits driving information of the own vehicle to vehicles that drive in the surrounding area. The vehicle determines a transmission frequency depending on a driving place of the own vehicle.
PTL 3 discloses a system in which a usage communication fee is calculated and a transmission interval is changed depending on a determination result whether or not to exceed a threshold value of the communication fee specified in advance.